According to a statement, the centenarian Field Marshal had joined the then Royal Nepal Army (RNA) at the age of 18 on 1 Shrawan 1988 B.S (1931) and was appointed to the post of Major at the Shri Pashupati Prasad Battalion.

Field Marshal Rana was posted at the Northwest Frontier Province in Rawalpindi of Pakistan and Burma during World War II.

[1] He married Khila Rajya Lakshmi, daughter of Yakshya Bikram Shah (a prominent aristocrat who was very popular in the royal palace).

They had a son and daughter together: However his wife who he loved dearly died at an early age and left him devastated.

Some years later he married Bimala Rajya Lakshmi from the Vazir family in Jammu in 1943 and they had a son: Field Marshal Nir Shumsher Jang Bahadur Rana died at the age of 99 on 27 October 2013 at the King Birendra Military Hospital in Chhauni, Kathmandu, while undergoing treatment.